I’m confused. What’s the difference between epidemic, pandemic, plague, and outbreak?

Potato, po-tat-o. (Is anyone else eating tons of potatoes this shelter-in-place?)
What is the right term for what’s happening right now? Besides the reality that this sucks and will probably continue to suck for the foreseeable future.
Epidemic. Pandemic. Plague. Outbreak. They’re all basically the same, right?
Apparently not. They are technical terms that refer to the scale that the disease spreads.
Taking our current situation as an example, the spread of coronavirus (officially SARS-COV-2) started as an outbreak in the Wuhan province of China in November and December 2019.
Outbreak
out·break
/ˈoutˌbrāk/
A sudden eruption of cases in a small area or region.
The spread quickly escalated and became an epidemic.
Epidemic
ep·i·dem·ic
/ˌepəˈdemik/
The rapid spread of a disease through a community.
When SARS-COV-2 hopped on the plane and came to Europe, US, Africa, everywhere?
Suddenly, the epidemic became a pandemic.
Pandemic
pan·dem·ic
/panˈdemik/
The rapid spread of a disease throughout the world.
The World Health Organization declared the coronavirus a pandemic on March 11, 2020. This is the first time a member of the coronavirus family of viruses (which cause respiratory tract infections in mammals) has caused a pandemic.
Humanity is no stranger to pandemics.
History’s most deadly pandemic was the bubonic plague (also known as the Black Death or Black Plague), which killed an estimated 200 million people (or half of Europe) in the 14th century.
The culprit was a bacteria carried by rats and spread to humans via infected fleas.
Although the origin remains a mystery, the 1918-1919 Spanish flu pandemic is estimated to have killed between 50 and 100 million people. More recently, the HIV/AIDS pandemic, which began in 1981, has killed an estimated 35 million.
We hear the word “plague” being batted around.
Does the current situation count as a plague?
Plague
plague
/plāɡ/
Can be used in place of outbreak, epidemic, or pandemic and useful for eliciting emotional reactions.
Plague is not really a useful term, scientifically. It does carry more emotional weight.
For many, the current situation can feel like a plague, or like a personal apocalypse. Our worlds are completely different now than they were. This can be very stressful for all of us.
Take a moment and prioritize feeling better. This is a marathon, not a race. We need to take care of ourselves today.